An animal with bilateral symmetry has right and left sides that mirror each other, along with distinctive anterior and posterior ends (head and tail). One such organism also possesses dorsal and ventral surfaces. Most often, the head contains the brain, sense organs, and mouth. Such symmetry fits the lifestyle of the animal. Like this bird, most bilaterally symmetric animals are very active and travel through their environment head first. This orientation allows their eyes, ears, and other sense organs to make initial contact with their surroundings. The data obtained by these senses allow the rest of their organs to adapt and react with maximum efficiency.